Potable water heater

ABSTRACT

A water heater for heating potable water used in a boat or vehicle has operating components which are easily accessible from one end of the heater. The heater further includes a water level sensor to indicate water quantity and a coolant stack which terminates in an exhaust stack which can have either of two configurations for installation flexibility.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a division of application Ser. No. 10/848,780, filedMay 18, 2004, currently pending, and entitled IMPROVED POTABLE WATERHEATER.

INTRODUCTION

This invention relates to a improved hot water heater and, moreparticularly, to an improved hot water heater for marine or vehicle useand which utilises diesel fuel for heating potable water and whichheater utilises the exhaust of the burner to improve the efficiency ofthe heating process.

BACKGROUND OF THE INVENTION

Hot water heaters for heating potable water for use in cooking, showers,baths and the like, and which potable water heaters are used inrecreational vehicles, boats, motor homes and other vehicles are, ofcourse, well known. The fuel typically used in such heaters is electricpower or propane. The disadvantages in using propane are well knownsince propane is maintained in its liquid state by a pressurized storagevessel. In a boat, the gas, being heavier than air, will accumulate inthe lower portions of the boat in the event there is a leak. The fuel isvolatile and if it is ignited, an explosion may occur. More mundaneconsiderations include the fact that propane fuel is not readilyavailable. Statutes and local regulations may require that such fuels bestored under stringent conditions and commercial outlets are thereforenot always at hand.

Yet a further consideration is the efficiency of the potable waterheater itself. In a boat or vehicle, the space available for a waterheater is at a premium. It is desirable to have the water heater take upa relatively small volume.

SUMMARY OF THE INVENTION

According to one aspect of the invention, there is provided a hot waterheating system with a burner and operating components associated withsaid burner, said burner and said operating components being locatedwithin a housing, said operating components being located at andaccessible form one end of said heating system upon removal of a portionof said housing.

According to a further aspect of the invention, there is provided acoolant level sensor in a heated coolant and diesel powered heater, saidcoolant level sensor producing a signal when said coolant within saidheater is beneath a predetermined level, said signal being operable toterminate operation of said heater.

According to yet a further aspect of the invention, there is provided acoolant heater for heating coolant and circulating said heated coolantthrough a boat, vehicle or other living area, said coolant heatercomprising a coolant stack carrying gases from a burner, said coolantstack being located within a coolant jacket and said coolant stackterminating in an exhaust stack releasing said hot gases to theatmosphere, said coolant stack being in a configuration that allows saidexhaust stack to exit said water heater at least two exhaust stack exitlocations.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

Specific embodiments of the invention will now be described, by way ofexample only, with the use of drawings in which:

FIGS. 1A and 1B are diagrammatic side and end views, respectively, of apotable water heater according to the invention;

FIG. 2 is a schematic of the circuit used with the water level sensoraccording to a further aspect of the invention;

FIG. 3 is an isometric and partial cutaway view of one end of the heateraccording to the invention particularly illustrating the accessibilityof the various components for serving and the water inlet and outlets;

FIG. 4 is a diagrammatic schematic of a zone heater which zone heater isused in operable association with the heater according to the invention;and

FIGS. 5A and 5B are diagrammatic end and side cutaway views of a furtherembodiment of the invention in which a heater according to the inventionmay be used in two different applications.

DESCRIPTION OF SPECIFIC EMBODIMENT

Referring now to the drawings, the potable water heating system isgenerally illustrated at 100 in FIG. 1A. The exhaust is created by acentrally located burner 101 which is conveniently diesel fuel poweredand which burner 101 utilises pressurized air for the nozzle 102 wherethe diesel fuel and the air combine to provide the combustion flame 122.The burner 101 is conveniently a burner utilised in a HURRICANE(Trademark) heating system manufactured by International ThermalResearch Ltd. of Richmond, British Columbia, Canada.

The heating system 100 includes an exhaust jacket 103 surrounding theburner 101 which exhaust jacket 103 conveys hot exhaust to an exhaustmanifold 104 and thence to a stack 110 which releases the hot gases tothe atmosphere, the direction of flow of the hot exhaust beingillustrated by the arrows.

A potable water jacket 110 surrounds the burner 101 and carries potablewater. Cold potable water enters the water jacket 110 at cold waterinlet 112 (FIG. 1B) and, after being heated by the hot gases in theexhaust jacket 103, the now heated potable water leaves at water outlet113.

An electrical or resistance element 114 is inserted into the waterjacket 110 from the end as illustrated in FIG. 1B. The electricalelement 114 is a resistance type 120 volt heater and is electricallypowered to assist in maintaining the temperature of the potable waterwhen the burner 101 is not operating such as when the vehicle or boathas an independent source of power available.

The heating system 100 is pressurized; that is, the heating system 100is a closed system. As such, there are forces acting on the end portions120, 121 of the water jacket 110. The end portions 120, 121 are eachgenerally convex on the outside surface and concave on the insidesurfaces 126, 127 which inside surfaces 126, 127 are exposed to thepotable water under pressure in the water jacket 110.

A water level sensor generally illustrated at 130 (FIG. 1B) is insertedinto the potable water heater 100. Water level sensor 130 is used tosense the presence of water within the heater 100. In the event thesensor 130 does not sense water within the heater 100, a signal 131 issent to a control board (not illustrated) which signal results in heatershutdown with the control board terminating operation of the burner 101.

Referring now to FIG. 3, one end of the heater 100 is illustrated. Itwill be appreciated that the heater 100 is conveniently installed in arecreational vehicle (not shown) from the end; that is, it is mountedendwise and, if servicing is required, it is conveniently done byopening access to one end of the heater 100 only so that the heater 100need not be removed in its entirety for servicing. To that end, a singleremovable and peripheral wrap around panel member partially shown at 140which covers the two sides and the top of the heater 100 is convenientlyattached with removable attachments 141 (one of which is shown) such asscrews, bolts and the like on opposite sides of the heater 100. Afurther and front panel member 142 is conveniently attached to the frontof the heater 100 and is similarly easily removed by removing itsattachment screws (not shown). When the end panel 142 and/or the sidepanel 140 are removed, the operating components of the heater 100 arereadily visible and manually accessible from the end of the heater 100and servicing is possible without the removal of the heater 100 from therecreational vehicle or boat. The burner assembly 143, the compressor144, the aquastats 150 mounted in the water jacket and at the end of thecombustion chamber, the combustion fan 151, and the fuel pump 152 areall readily accessible to a user of the heater 100 and may be removedand serviced from the end of the heater 100 without removal of theheater 100 from the vehicle in which it is installed. In addition, thecold water inlet 153 and the hot water outlet 154 are similarlyconveniently located at the end of the heater 100 with a mixing valve160 also conveniently located at the end of the heater 100 for access.

Operation

In operation, ignition of the fuel and air will take place as is usual,such as with the use of an ignition electrode (not shown) and acombustion flame 122 will appear in the burner tube 101 from thecombustion of the pressurized air and fuel combined in the nozzle 102(FIG. 1A). Hot gases will subsequently emanate from the combustion flame122 and leave the end of the burner tube 101 as is shown by the arrows,the hot gases traveling first into the exhaust jacket 103 to a firststack 124 which transfers the exhaust gases to a second passageway 104located within the water jacket 110 of the burner 100. The exhaust willexit the second passageway 104 through outside stack 110 andsubsequently is released to the atmosphere.

Thus, it will be seen that the heat from the exhaust gases are used toheat the exhaust manifold 104 which manifold is in contact with thepotable water within the heater 100. Additional heat is thereforeprovided to the potable water through the exhaust manifold 104 which,because of its location within the potable water jacket 110, willenhance the heating of the potable water prior to the exhaust gasesbeing released to the atmosphere and improve the efficiency of theburner. A further advantage is that the stack temperature will be reducebecause heat in the exhaust gases will be transferred to the potablewater before the exhaust gases reach stack 100.

Because the water is under pressure within the water jacket 110, theforce of the water will act against the end portions 120, 121 of thewater heater 100. This force may be intermittent with the result thatcyclical stress arises. It has been found that having the end portions120, 121 assume a convex outside configuration and a concave insideconfiguration will reduce the amplitude of the cyclic stress on heater100. The forces acting on the end portions, therefore, are betterabsorbed by the housing of the heater 100.

Access to the operating components associated with the combustion inheater 100 is conveniently provided by the removable side and end panels140, 142 respectively (FIG. 3). The user or operator may unscrew theattachment screws 141 and remove the side and top panel 140 and likewiseremove the end panel 142. The burner assembly 143 may then be removedfor servicing. If the other operating components need servicing orreplacement such as the compressor 144, the combustion fan 151, the fuelpump 152 or the aquastats 150, their location on one end of the heater100 conveniently provides access without removal of the heater 100 fromthe vehicle and without the necessity of removing panels other thanthose located at one end of the heater 100. Similarly, the mixing valve160 may easily be adjusted for raising or lowering the temperature ofthe hot water exiting the water heater 100 from hot water outlet 154.

A further embodiment of the invention is illustrated in FIG. 4 fromwhich a zone heater generally illustrated at 161 is operably connectedto the potable water heater 100. Zone heater 161 conveniently includes afan 162 which blows air over a radiator within the zone heater 161. Aglycol mixture circulates through the zone heater 161 and a heatexchanger 163 by the use of a pump 164 which is operably connected to anaquastat 170 which measures the temperature of the circulating glycolmixture. An expansion tank 170 is conveniently provided in the circuitof the zone heater 162.

A second pump 172 and an associated aquastat 173 are provided to pumpthe potable water heated within the potable water heater 100 through theheat exchanger 163 thereby to exchange heat with the glycol mixturecirculating through the zone heater 161. The pumps 164, 171 areinitiated by a thermostat located in the zone serviced by the zoneheater 161.

Reference is now made to FIGS. 5A and 5B which illustrate an improvedefficiency heater similar to the potable water heater 100 of FIGS. 1Aand 1B. In this embodiment, however, a coolant other than potable watermay be used with the same efficiencies, such a coolant being, forexample, glycol. A further aspect of the FIG. 5 embodiment lies in aconfiguration which may be adapted for heater use in two(2)installations. The first installation, as shown in FIG. 5B, incorporatesa final exhaust stack 180 which extends downwardly within the heater 181and exits the heater 181 from the bottom. This exhaust configuration mayconveniently be used for recreational vehicles and other vehicles wherethe exhaust is routed along the bottom of the vehicle. A second finalexhaust configuration is shown in broken lines at 182. A hole is cut inthe top of coolant stack 183 and the final exit or exhaust stack 182 isconnected and exits the top of the coolant heater 181. Electric elements190, 191 are conveniently provided to heat the coolant when electricpower is available. Cold coolant enters the coolant heater at 192 andmay conveniently exit the heater 181 at 193 although ingress and egressof the coolant may be similar to that in the FIG. 1 embodiment. Otheroperating configurations particularly described in association with theFIG. 1 embodiment may likewise be useful in the FIG. 5 embodiment.

Many modifications will readily occur to those skilled in the art towhich the invention relates. For example, although the exhaust stack isshown to be in a rectangular configuration as viewed in FIG. 2, theshape could of course change as design circumstances change and whilethe exhaust stack is shown as traveling down only one side of the waterjacket 110, the hot exhaust could also travel within the water jacket110 in several other configurations on various sides of the burner tube101 and on each side of the burner tube 101 if desired. And while onlyone pass of the hot exhaust through the water jacket 114 is describedand illustrated, more than one pass for the hot exhaust is readilycontemplated.

It is further contemplated that the potable water heater according tothe invention may conveniently be used in a living environment otherthan in marine or vehicle use. Such a heater requires initial power toinitiate the combustion flame but, following that ignition, the heatercould operate on minimal power or the energy generated by the heatercould be used to produce the necessary power for continued operation.

Many further embodiments will readily occur to those skilled in the artto which the invention relates and the particular embodiments describedare given by way of example only and are not intended as limiting thescope of the invention as defined in accordance with the accompanyingclaims.

1. A hot water heating system with a burner and operating componentsassociated with said burner, said burner and said operating componentsbeing located within a housing, said operating components being locatedat and accessible form one end of said heating system upon removal of aportion of said housing.
 2. A hot water heating system as in claim 1wherein said operating components include a burner assembly, acompressor, a combustion fan and a fuel pump.
 3. A hot water heatingsystem as in claim 2 and further comprising a hot water outlet and acold water inlet located at said one end of said heating system.
 4. Ahot water heating system as in claim 3 which utilises a coolant andfurther comprising a coolant level sensor which produces a signal whensaid coolant within said heater is beneath a predetermined level, saidsignal being operable to terminate operation of said burner.
 5. A hotwater heating system as in claim 4 wherein coolant replaces said water,said heater circulating said heated coolant through a boat, vehicle orother living area, said heater comprising a coolant stack carrying gasesfrom a burner, said coolant stack being located within a coolant jacketand said coolant stack terminating in an exhaust stack releasing saidhot gases to the atmosphere, said coolant stack being in a configurationthat allows said exhaust stack to exit said water heater at least twoexhaust stack exit locations.
 6. A coolant level sensor in a heatedcoolant and diesel powered heater, said coolant level sensor producing asignal when said coolant within said heater is beneath a predeterminedlevel, said signal being operable to terminate operation of said heater.7. A coolant level sensor as in claim 6 wherein said coolant is water.8. Coolant heater for heating coolant and circulating said heatedcoolant through a boat, vehicle or other living area, said coolantheater comprising a coolant stack carrying gases from a burner, saidcoolant stack being located within a coolant jacket and said coolantstack terminating in an exhaust stack releasing said hot gases to theatmosphere, said coolant stack being in a configuration that allows saidexhaust stack to exit said water heater at at least two exhaust stackexit locations.